Reset interception to avoid data loss in storage device resets

ABSTRACT

Apparatus and methods are disclosed, including a controller circuit, a volatile memory, a non-volatile memory, and a reset circuit, where the reset circuit is configured to receive a reset signal from a host device and actuate a timer circuit. The timer circuit, where the timer circuit is configured to cause a storage device to reset after a threshold time period. The reset circuit is further configured to actuate the controller circuit to write data stored in the volatile memory to the non-volatile memory before the storage device is reset.

PRIORITY APPLICATION

This application is a continuation of U.S. application Ser. No.16/236,785, filed Dec. 31, 2018, which is incorporated herein byreference in its entirety.

TECHNICAL FIELD

Embodiments of the present disclosure relate generally to computerstorage systems, more particularly, but not by way of limitation, tointercepting reset signals to delay a reset event, to avoid data loss instorage device resets.

BACKGROUND

Computer storage systems can use one or more data storage devices tostore or retrieve data that is generated or operated on by hostcomputing systems. Such storage devices can include one or more storagecontrollers that use a combination of firmware and hardware componentsto facilitate the movement of data between a host computing system andstorage media associated with the storage devices. A storage device,however, can be become deadlocked, or can otherwise malfunction in a waythat can cause the storage device to become unresponsive to commandsissued by a host computing system. To enhance the reliability ofcomputing systems, storage devices can incorporate functionally thatreset these devices in response to receiving a reset signal from hostsystem.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, which are not necessarily drawn to scale, like numeralscan describe similar components in different views. Like numerals havingdifferent letter suffixes can represent different instances of similarcomponents. The drawings illustrate generally, by way of example, butnot by way of limitation, various embodiments discussed in the presentdocument.

FIG. 1 illustrates an example host system including a host device and astorage system, in accordance with examples of the present disclosure.

FIG. 2 illustrates an example a process for intercepting a reset signalfrom a host device to avoid data loss in a storage device reset, inaccordance with examples of the present disclosure.

FIG. 3 illustrates an example a process for responding to a reset signalto avoid data loss in a storage device reset, in accordance withexamples of the present disclosure.

FIG. 4 illustrates an example a computer system having a data storagesystem to perform any one or more of the processes or techniquesdiscussed herein, in accordance with examples of the present disclosure.

DETAILED DESCRIPTION

Aspects of the present disclosure are directed to limiting, or reducing,data loss in storage systems during a storage device reset. Inoperation, a storage device can receive data from a host device to writeto a storage medium. Writing such data directly to a storage medium canbe expensive, such as in terms of time, energy, and other computingresources used to execute the write operation. In an example, a storagedevice can include a solid-state drive (SSD) having arrays of flashmemory cells as a storage medium. Each write to the array of flashmemory cells can consume a lot of time and energy because such writeoperations can require write data to be presented to the array for anindicated threshold time while the cells are actuated at a relativelyhigh voltage. Additionally, partial writes, such as write operationsthat do not include enough data to fill a string to memory cells of aspecified length, can waste storage, while frequent writes can reducethe useful lifetime of the storage media. A storage device can reducethe costs associated with executing such write operations by temporarilystoring write data received from a host device in a memory buffer, acache, or other volatile memory (collectively referred to hereinafter asa “write cache”). Data in the write cache can then be written to astorage medium at a time specified by one or more storage or cachemanagement algorithms.

In some situations, a storage device can malfunction, or can otherwisebe perceived as unresponsive to host commands. In these situations, ahost device can transmit a reset signal to the storage device to causethe storage device to perform a reset. For purposes of the presentdescription, a reset operation is one that either expressly results influshing of any data within a write cache, or inherently creates a riskof loss of data within a write cache. Performing a reset can includeimmediately resetting internal logic circuits, memory circuits (e.g.,volatile memory circuits), and or other components of a storage deviceto put the storage device to a specified operating state. In somesituations, a host device can trigger a reset in a normally functioningstorage device, such as a storage device that is still under the controlof programmed firmware being executed by its storage controller. Datathat is stored in a write cache these devices, and waiting to be writtento a storage medium, can be lost when a storage device executes thereset.

Aspects of the present disclosure are based on the inventor'srecognition that unwritten data stored in a write cache of a functioningstorage device can be preserved by intercepting a reset signaltransmitted by a host device and causing the storage device to write theunwritten data to a storage medium before executing a reset.Accordingly, the present disclosure includes techniques (e.g., systems,methods, machine readable storage media) for intercepting reset signalsto limit, or avoid, data loss in storage device resets. Such techniquescan include intercepting a reset signal transmitted by a host device toa storage device, such as to prevent the storage device from immediatelyexecuting a reset. Such techniques can also include starting a timer todelay the reset for an indicated or threshold amount of time. Suchtechniques can also include triggering, such as in response to receivinga reset signal or in response to starting the timer, a processorinterrupt such as to cause a storage controller, or other controlcircuit associated with the storage device, to disable the timer, writethe unwritten data to the storage medium, and execute the reset (e.g., asoft reset or a hard reset) after writing the unwritten data.

FIG. 1 illustrates an example host system 100 including a host device105 and a storage device 110, in accordance with examples of the presentdisclosure. The host system 100 can be any computing system configuredwith devices that generate, store, access, or otherwise operate on, orcommunicate, digital data. The host system 100 can be a standalonecomputing system, such as a server. The host system 100 can also be adistributed computing system, including one or more host devices 105 andstorage devices 110.

The host device 105 can be a device that is associated with the hostsystem 100 and configured to write data to, or to read data from, thestorage device 110. The host device 105 can include a host processor, acentral processing unit, or one or more other computing device,processor, controller, or control circuitry. The host device 105 canalso include a communication interface (I/F), such as a bidirectionalparallel or serial communication interface, to communicate with thestorage device 110 or the host system 100. Examples of the communicationinterface can include, but are not limited to, a serial advancedtechnology attachment (SATA) interface, a peripheral componentinterconnect express (PCIe) interface, universal serial bus (USB)interface, Fibre Channel, Serial Attached SCSI (SAS), an eMMC™interface, etc. Such communication interface can include one or morecontrol or data channels (e.g., a DATA/CONTROL), such as to enable thehost device 105 to transfer data between the host device and the storagedevice 110. Such communication interface can also include a RESETchannel, such as for transmitting a reset signal to the storage device110. In an example, the RESET channel can include a physical electricalconductor that couples the host device 105 to a reset port or interfaceof the storage device 110.

The storage device 110 can be in the form of, or can include, auniversal flash storage (UFS) device, an embedded MMC (eMMC™) device, orone or more other memory devices. For example, if the storage device 110includes a UFS device, the communication interface used to couple thehost device 105 to the storage device can include a serial bidirectionalinterface, such as defined in one or more Joint Electron DeviceEngineering Council (JEDEC) standards (e.g., JEDEC standard D223D(JESD223D), commonly referred to as JEDEC UFS Host Controller Interface(UFSHCI) 3.0, etc.). In another example, if the storage device 110includes an eMMC device, the communication interface used to couple thehost device 105 to the storage device can include a number of parallelbidirectional data lines (e.g., DAT[7:0]) and one or more command lines,such as defined in one or more JEDEC standards (e.g., JEDEC standardD84-B51 (JESD84-A51), commonly referred to as JEDEC eMMC standard 5.1,etc.). In other examples, the storage device 110 can include one or moreother memory devices, or the communication interface used to couple thehost device 105 to the storage device.

The storage device 110 can include a storage controller 115, and storagearray 140, and reset logic 145. In some examples, the reset logic 145can be a component of the storage controller 115. Generally, the storagedevice 110 can be in the form of, or at least include, a discretestorage device, such as a system on chip (SOC); or an integrated storagedevice and controller (examples of which are devices compliant with theabove-discussed UFS or eMMC specifications, or an SSD), and can beconfigured to perform the operations and techniques described herein.

The storage controller 115 can include a processor (processing device)or other control circuitry configured to execute firmware instructions120 to perform the operations and techniques described herein. In someexamples, the storage controller 115 can be a microcontroller, specialpurpose logic circuitry (e.g., a field programmable gate array (FPGA),an application specific integrated circuit (ASIC), etc.), or othersuitable processor. The storage controller 115 can include a firmwareinstructions or circuitry 120, buffer memory, such as write cache 135,and other hardware circuits, such as one or more integrated circuitsand/or discrete components. The storage controller 115 can receiveinstructions from the host device 105, and can communicate with thestorage array 140, such as to transfer data to (e.g., write or erase) orfrom (e.g., read) the storage array.

The firmware 120 can include computer code or instructions that areexecutable by the storage controller 115 to perform operations totransfer data to, or from, the storage array 140. In some examples, thefirmware 120 can be encoded in one or more hardware circuits associatedwith the storage controller 120. The firmware 125 can include, amongstother things, a reset interrupt service routine (ISR) 125, and a dataflush routine 140. In some examples, the reset ISR 125 and the dataflush routine 140 can be included in the same firmware routine.

The reset ISR 125 can include firmware instructions that are executed bythe storage controller 115 in response to actuation of the storagecontroller input port, or pin, IRQ_IN. Such actuation can includedriving IRQ_IN with any signal that can be detected by the storagecontroller 115 and used to trigger execution of the reset ISR 125. Thestorage controller 115 can be configured to trigger a processorinterrupt when IRQ_IN is actuated. An interrupt vector associated withthe triggered processor interrupt can be configured to cause the storagecontroller 115 to suspend other processes being executed by the storagecontroller and to execute the reset ISR 125. The reset ISR 125 caninclude instructions that, when executed, causes the storage controller115 to disable a timer circuit 155 in the reset logic 145, such as byactuating the storage controller output port, or pin, disable_out. Insome examples, the reset ISR 125 can allow the timer in the reset logic145 to continue to run. In these examples, firmware instructions in thereset ISR can be executed to cause the storage controller to adjust acurrent count, or a target count, of the timer, such as to delay thereset of the storage device 110. The reset ISR 125 can also includefirmware instructions that, when executed, causes the storage controller115 to execute the data flush routine 130.

The data flush routine 130 can include firmware instructions that, whenexecuted, causes the storage controller 115 to write unwritten data(e.g., data received from the host device 105 for writing to the storagedevice 110, but which has not been written to the storage array 140)stored in the write cache 135 to the storage array 140.

Either the reset ISR 125, the data flush routine 130, or anotherfirmware routine included in the firmware 120, can include firmwareinstructions that, when executed, causes the storage controller 115 toreset the storage device 110 after the unwritten data stored in thewrite cache 135 is written to the storage array 140. In some examples,the storage controller 115 can reset the storage device 110 byreenabling the timer circuit 155 in the reset logic 145 and allowing thetimer to expire (e.g., allowing the timer to count up to, or down from,a target value). In certain examples, the storage controller 115 canreset the storage device 110 by allowing a timer circuit in the resetlogic 145, when the timer is not disabled by the reset ISR 125, toexpire, such as by not adjusting the current value of the timer or thetarget value of the timer. In other examples, the storage controller canreset the storage device 110 by actuating one or more hardware circuitsthat are configured to execute the reset.

Returning the discussion of the components of the storage controller115, the write cache 135 can include an array of memory cells to whichdata can be written at a lower cost than writing data to the storagearray 140. In an example, the write cache 135 can include arrays ofstatic memory, such as an array of static random access memory (SRAM).In other examples, the write cache 135 can include arrays of dynamicrandom access memory (DRAM) or persistent memory, such as randomlyaddressable memory that is preserved through a power cycle. The writecache 135 typically includes volatile memory, but some non-volatilememory technologies can be used in the write cache provided that suchtechnologies enable data to be written at a lower cost (e.g., faster)than the cost for writing data to the storage array 140.

The storage array 140 can be configured to provide non-volatile storagefor data received from the host device 105. Such non-volatile storagecan be provided by one or more types of non-volatile memory devices,such as NAND flash memory devices or NOR flash memory devices. Suchnon-volatile memory devices can include one or more arrays of memorycells such as single-level cells (SLCs) or multi-level cells (MLCs)(e.g., triple-level cells (TLCs) or quad-level cells (QLCs)). In someconventional industry usage, the term MLC has been used to identifymemory cells that can store two bits of data per cell (e.g., one of fourprogrammed states); but is also utilized in a broader context to referto memory cells that can store more than one bit of data per cell (i.e.,that can represent more than two programmed states). Unless clearlyindicated otherwise by express language or context, MLC is used hereinin the broader context and includes, for example, TLC and QLC memorycells. Each of the memory cells can be configured to store bits of data(e.g., data blocks) received from the host device 105. In some examples,the storage array 140 can include random access memory (RAM), such asbattery-backed RAM. In other examples, the storage array 140 can includeread-only memory (ROM), phase change memory (PCM), magneto random accessmemory (MRAM), and electrically erasable programmable read-only memory(EEPROM).

The reset logic 145 can include one or more circuits or firmwareinstructions for intercepting a reset signal from the host device 105and causing the storage device 110 to write unwritten data stored in thewrite cache 135 to the storage array 140 before executing a reset, asdescribed herein. The reset logic 145 can include control logic 150 anda timer 155. The control logic 150 can include one or more circuits toreceive, or intercept, a reset signal transmitted by the host device 105to the storage device 110.

In an example, the control logic 150 can also include one or morecircuits to initialize the timer 155 with an indicated value, such as anumber of timer ticks or units of time that must pass before the resetlogic 145 executes a reset. In some examples, the timer 155 can includea decrementing counter, and initializing the timer can include storing acountdown value in the counter and triggering the timer to periodicallydecrement the counter. In some examples, the timer 155 can include a upcounter and a target value register or other storage element, andinitializing the timer can include storing an indicated value in thetarget counter and triggering the timer to start counting up to theindicated value. Once initialized the timer circuit 155 can count for anindicated time period. At the end of the indicated time period, thetimer circuit 155 can trigger, or cause, an automatic reset of thestorage device 115. The automatic reset, however, can be avoided bydisabling the timer 155 before the indicated time period.

In another example, the control logic 150 can include one or morecircuits for generating an interrupt in the storage controller 115, suchas by actuating the IRQ_OUT signal. The control logic 150 can actuatethe IRQ_OUT signal in response to receiving the reset signal form thehost device 105. In some examples, the control logic 150 can actuate theIRQ_OUT signal at substantially the same time that the timer 155 isinitialized. Such one or more circuits can also cause the reset logic145 to determine that the timer 155 has expired (e.g., the timer counteddown to zero, or a value of the timer reached an indicated timer value)and trigger the execution of the reset, such as by actuating one or morecircuits in the controller 115, or the one or more circuits in thestorage device 110, to execute the reset.

In operation, the host device 105 can execute data transfer operationsto write data to, or to read data from, the storage device 110. Thestorage controller 115 can service the data transfer operation on thebehalf of the storage device 110, such as by executing firmware 120 towrite data to, or to read data from, the storage array 140. The storagecontroller 115 can service data write operations issued by the hostdevice 105 by executing the firmware 120 to buffer or store write dataassociated with one or more write operations in the write cache, andthen write the buffered write data to the storage array according to anindicated write data caching algorithm.

The host device 105 can monitor the communication interface between thehost device and the storage device 110, such as to determine whether thestorage device is functioning or communicating normally. The storagedevice 110 can appear to be malfunctioning, or can appear to not becommunicating normally, when, amongst other things, communicationsbetween the host device 105 and the storage device is interrupted, suchas because the storage controller is deadlocked or there is interferenceon the communication interface.

The host device 105 can issue a hardware reset to the storage device 110in response to determining that the storage device 110 ismalfunctioning, or is not communicating normally, or for other reasons.The reset logic 145 can intercept the reset signal and initialize andstart the timer 115. The reset logic 150 can also trigger an interruptin the storage controller 115 at substantially the same time that thetimer 155 is initialized or started.

If the storage controller 115 is function normally (e.g., the storagecontroller is able to respond to processor interrupts), the reset ISR125 can service the interrupt by disabling the timer 155 and executingthe data flush routine 130 to write unwritten data stored in the writecache 135 to the storage array 150. Firmware in the storage controller115 can then be executed to cause the storage device 110 to execute thereset.

If the storage controller 115 is deadlocked or otherwise malfunctioning(e.g., the storage controller is not able to respond to processorinterrupts), the timer 155 will continue to tick or count until thetimer expires (e.g., until threshold time period has elapsed) or anindicated timeout value is reached. The reset logic 150 can then causethe storage device 110 to execute the reset, as described herein.

FIG. 2 illustrates an example a process 200 for intercepting a resetsignal from a host device to avoid data loss in a storage device reset,in accordance with examples of the present disclosure. The host devicecan be an example of the host device 105 (FIG. 1), while the storagedevice can be an example of the storage device 110 (FIG. 1). The process200 can be executed by hardware circuits or firmware components of thestorage device.

At 205, a reset signal, such as a reset signal, can be received from ahost device. The host device can transmit the reset signal in responseto the determining that the storage device is malfunctioning or notcommunicating properly, or for another reason.

At 210, a timer can be actuated to cause the storage device to restafter a threshold time period. Actuating the timer can includeinitializing the timer to count up to, or down from, an indicated value,as described herein.

At 215, the storage device can be actuated to write data stored in awrite cache or volatile memory associated with a storage controller ofthe of the storage device to a storage array or other non-volatilememory coupled to the storage controller before resetting the storagedevice. Actuating the storage device can include triggering an interruptin the storage controller to transfer process execution in the storagecontroller to an ISR, such as the reset ISR 125 (FIG. 1). If thecontroller is functioning, the reset ISR can then cause the storagecontroller to disable the timer, write unwritten data stored a writecache of the storage controller to non-volatile memory, and reset thestorage controller, as will be described in the discussion of FIG. 3.

At 220, if the timer was not disabled at operation 215, it can bedetermined whether the timer indicates that are threshold time periodfor delaying the reset was reached. Determining whether the thresholdtime period was reached can include determining whether a counterassociated with the timer has incremented to an indicated value, ordetermining whether a counter associated with the timer has sufficientlydecremented from an indicated value. The process 200 can be continued at215 when the timer was not disabled and threshold time period has notbeen reached, while the process can proceed to operation 225 when thetimer was not disabled and threshold time period has been reached.

At 225 a reset operation can be executed to reset the storage device, asdescribed herein.

In some examples, the process 300 can be executed instead of operations220 and 225, such as when a healthy (e.g., normally functioning) storagecontroller disables the timer at 215. In other examples, operations 220and 225 can be executed instead of the process 300, such as when amalfunctioning storage controller fails to respond or deactivate thetimer at 215.

FIG. 3 illustrates an example a process for responding to a reset signalto avoid data loss in a storage device reset, in accordance withexamples of the present disclosure. As discussed herein, the operations300 can be executed by a storage controller, such as the storagecontroller 115, to actuate the storage device to write data stored inthe volatile memory to the non-volatile memory before resetting thestorage device, as shown in operation 215 (FIG. 2).

At 305, the storage controller can receive a signal that generates aprocessor interrupt. The signal can be received from a reset logiccomponent of a storage device, such as the reset logic component 145(FIG. 3). The storage controller can be configured to case the receivedsignal to generate the highest priority interrupt serviceable by thestorage controller, such as to cause the storage controller toimmediately suspend execution of any current processes to service thetriggered interrupt.

At 310, the storage controller can disable the reset timer, such as toprevent the automatic reset of the storage device at the expiration ofthe rest timer.

At 315, the storage controller can write (e.g., flush) unwritten datastored in a write cache (e.g., volatile memory) of the storagecontroller, such as the write cache 135 (FIG. 1), to a non-volatilestorage medium associated with the storage controller, such as thestorage array 140.

At 320, the storage device can be reset, as described herein.

FIG. 4 illustrates an example a computer system 400 having a datastorage device to perform any one or more of the processes or techniquesdiscussed herein, in accordance with examples of the present disclosure.The computer system 400 can be an example of the host system 100 (FIG.1), while the data storage device can be an example to the storagedevice 110 (FIG. 1).

In alternative embodiments, the machine 400 can operate as a standalonedevice or can be connected (e.g., networked) to other machines. In anetworked deployment, the machine 400 can operate in the capacity of aserver machine, a client machine, or both in server-client networkenvironments. In an example, the machine 400 can act as a peer machinein peer-to-peer (P2P) (or other distributed) network environment. Themachine 400 can be a personal computer (PC), a tablet PC, a set-top box(STB), a personal digital assistant (PDA), a mobile telephone, a webappliance, an IoT device, automotive system, or any machine capable ofexecuting instructions (sequential or otherwise) that specify actions tobe taken by that machine. Further, while only a single machine isillustrated, the term “machine” shall also be taken to include anycollection of machines that individually or jointly execute a set (ormultiple sets) of instructions to perform any one or more of themethodologies discussed herein, such as cloud computing, software as aservice (SaaS), other computer cluster configurations.

Examples, as described herein, can include, or can operate by, logic,components, devices, packages, or mechanisms. Circuitry is a collection(e.g., set) of circuits implemented in tangible entities that includehardware (e.g., simple circuits, gates, logic, etc.). Circuitrymembership can be flexible over time and underlying hardwarevariability. Circuitries include members that may, alone or incombination, perform specific tasks when operating. In an example,hardware of the circuitry can be immutably designed to carry out aspecific operation (e.g., hardwired). In an example, the hardware of thecircuitry can include variably connected physical components (e.g.,execution units, transistors, simple circuits, etc.) including acomputer-readable medium physically modified (e.g., magnetically,electrically, moveable placement of invariant massed particles, etc.) toencode instructions of the specific operation. In connecting thephysical components, the underlying electrical properties of a hardwareconstituent are changed, for example, from an insulator to a conductoror vice versa. The instructions enable participating hardware (e.g., theexecution units or a loading mechanism) to create members of thecircuitry in hardware via the variable connections to carry out portionsof the specific tasks when in operation. Accordingly, thecomputer-readable medium is communicatively coupled to the othercomponents of the circuitry when the device is operating. In an example,any of the physical components can be used in more than one member ofmore than one circuitry. For example, under operation, execution unitscan be used in a first circuit of a first circuitry at one point in timeand reused by a second circuit in the first circuitry, or by a thirdcircuit in a second circuitry at a different time.

The machine (e.g., computer system, a host system, etc.) 400 can includea processing device 402 (e.g., a hardware processor, a centralprocessing unit (CPU), a graphics processing unit (GPU), a hardwareprocessor core, or any combination thereof, etc.), a main memory 404(e.g., read-only memory (ROM), dynamic random-access memory (DRAM) suchas synchronous DRAM (SDRAM) or Rambus DRAM (RDRAM), etc.), a staticmemory 406 (e.g., static random-access memory (SRAM), etc.), and astorage system 418, some or all of which can communicate with each othervia a communication interface (e.g., a bus) 430.

The processing device 402 can represent one or more general-purposeprocessing devices such as a microprocessor, a central processing unit,or the like. More particularly, the processing device can be a complexinstruction set computing (CISC) microprocessor, reduced instruction setcomputing (RISC) microprocessor, very long instruction word (VLIW)microprocessor, or a processor implementing other instruction sets, orprocessors implementing a combination of instruction sets. Theprocessing device 402 can also be one or more special-purpose processingdevices such as an application specific integrated circuit (ASIC), afield programmable gate array (FPGA), a digital signal processor (DSP),network processor, or the like. The processing device 402 can beconfigured to execute instructions 426 for performing the operations andsteps discussed herein. The computer system 400 can further include anetwork interface device 408 to communicate over a network 420.

The storage system 418 can include a machine-readable storage medium(also known as a computer-readable medium) on which is stored one ormore sets of instructions 426 or software embodying any one or more ofthe methodologies or functions described herein. The storage system 418can also include reset logic component 428, which can be configuredaccording to the techniques and methodologies of the present disclosure,such as perform the operations of the reset logic component 145. Theinstructions 426 can also reside, completely or at least partially,within the main memory 404 or within the processing device 402 duringexecution thereof by the computer system 400, the main memory 404 andthe processing device 402 also constituting machine-readable storagemedia.

The term “machine-readable storage medium” should be taken to include asingle medium or multiple media that store the one or more sets ofinstructions, or any medium that is capable of storing or encoding a setof instructions for execution by the machine and that cause the machineto perform any one or more of the methodologies of the presentdisclosure. The term “machine-readable storage medium” shall accordinglybe taken to include, but not be limited to, solid-state memories,optical media, and magnetic media. In an example, a massedmachine-readable medium comprises a machine-readable medium with aplurality of particles having invariant (e.g., rest) mass. Accordingly,massed machine-readable media are not transitory propagating signals.Specific examples of massed machine-readable media can include:non-volatile memory, such as semiconductor memory devices (e.g.,Electrically Programmable Read-Only Memory (EPROM), ElectricallyErasable Programmable Read-Only Memory (EEPROM)) and flash memorydevices; magnetic disks, such as internal hard disks and removabledisks; magneto-optical disks; and CD-ROM and DVD-ROM disks.

The machine 400 can further include a display unit, an alphanumericinput device (e.g., a keyboard), and a user interface (UI) navigationdevice (e.g., a mouse). In an example, one or more of the display unit,the input device, or the UI navigation device can be a touch screendisplay. The machine a signal generation device (e.g., a speaker), orone or more sensors, such as a global positioning system (GPS) sensor,compass, accelerometer, or one or more other sensor. The machine 400 caninclude an output controller, such as a serial (e.g., universal serialbus (USB), parallel, or other wired or wireless (e.g., infrared (IR),near field communication (NFC), etc.) connection to communicate orcontrol one or more peripheral devices (e.g., a printer, card reader,etc.).

The instructions 426 (e.g., software, programs, an operating system(OS), etc.) or other data are stored on the storage system 418 can beaccessed by the main memory 404 for use by the processing device 402.The main memory 404 (e.g., DRAM) is typically fast, but volatile, andthus a different type of storage than the storage system 418 (e.g., anSSD), which is suitable for long-term storage, including while in an“off” condition. The instructions 426 or data in use by a user or themachine 400 are typically loaded in the main memory 404 for use by theprocessing device 402. When the main memory 404 is full, virtual spacefrom the storage system 418 can be allocated to supplement the mainmemory 404; however, because the storage system 418 device is typicallyslower than the main memory 404, and write speeds are typically at leasttwice as slow as read speeds, use of virtual memory can greatly reduceuser experience due to storage system latency (in contrast to the mainmemory 404, e.g., DRAM). Further, use of the storage system 418 forvirtual memory can greatly reduce the usable lifespan of the storagesystem 418.

The instructions 424 can further be transmitted or received over anetwork 420 using a transmission medium via the network interface device408 utilizing any one of a number of transfer protocols (e.g., framerelay, internet protocol (IP), transmission control protocol (TCP), userdatagram protocol (UDP), hypertext transfer protocol (HTTP), etc.).Example communication networks can include a local area network (LAN), awide area network (WAN), a packet data network (e.g., the Internet),mobile telephone networks (e.g., cellular networks), Plain Old Telephone(POTS) networks, and wireless data networks (e.g., Institute ofElectrical and Electronics Engineers (IEEE) 802.11 family of standardsknown as Wi-Fi®, IEEE 802.16 family of standards known as WiMax®), IEEE802.15.4 family of standards, peer-to-peer (P2P) networks, among others.In an example, the network interface device 408 can include one or morephysical jacks (e.g., Ethernet, coaxial, or phone jacks) or one or moreantennas to connect to the network 420. In an example, the networkinterface device 408 can include a plurality of antennas to wirelesslycommunicate using at least one of single-input multiple-output (SIMO),multiple-input multiple-output (MIMO), or multiple-input single-output(MISO) techniques. The term “transmission medium” shall be taken toinclude any intangible medium that is capable of storing, encoding, orcarrying instructions for execution by the machine 400, and includesdigital or analog communications signals or other intangible medium tofacilitate communication of such software.

The above detailed description includes references to the accompanyingdrawings, which form a part of the detailed description. The drawingsshow, by way of illustration, specific embodiments in which theinvention can be practiced. These embodiments are also referred toherein as “examples”. Such examples can include elements in addition tothose shown or described. However, the present inventor alsocontemplates examples in which only those elements shown or describedare provided. Moreover, the present inventor also contemplates examplesusing any combination or permutation of those elements shown ordescribed (or one or more aspects thereof), either with respect to aparticular example (or one or more aspects thereof), or with respect toother examples (or one or more aspects thereof) shown or describedherein.

All publications, patents, and patent documents referred to in thisdocument are incorporated by reference herein in their entirety, asthough individually incorporated by reference. In the event ofinconsistent usages between this document and those documents soincorporated by reference, the usage in the incorporated reference(s)should be considered supplementary to that of this document; forirreconcilable inconsistencies, the usage in this document controls.

In this document, the terms “a” or “an” are used, as is common in patentdocuments, to include one or more than one, independent of any otherinstances or usages of “at least one” or “one or more.” In thisdocument, the term “or” is used to refer to a nonexclusive or, such that“A or B” includes “A but not B,” “B but not A,” and “A and B,” unlessotherwise indicated. In the appended claims, the terms “including” and“in which” are used as the plain-English equivalents of the respectiveterms “comprising” and “wherein”. Also, in the following claims, theterms “including” and “comprising” are open-ended, that is, a system,device, article, or process that includes elements in addition to thoselisted after such a term in a claim are still deemed to fall within thescope of that claim. Moreover, in the following claims, the terms“first,” “second,” and “third,” etc. are used merely as labels, and arenot intended to impose numerical requirements on their objects.

In various examples, the components, controllers, processors, units,engines, or tables described herein can include, among other things,physical circuitry or firmware stored on a physical device. As usedherein, “processor” means any type of computational circuit such as, butnot limited to, a microprocessor, a microcontroller, a graphicsprocessor, a digital signal processor (DSP), or any other type ofprocessor or processing circuit, including a group of processors ormulti-core devices.

The term “horizontal” as used in this document is defined as a planeparallel to the conventional plane or surface of a substrate, such asthat underlying a wafer or die, regardless of the actual orientation ofthe substrate at any point in time. The term “vertical” refers to adirection perpendicular to the horizontal as defined above.Prepositions, such as “on,” “over,” and “under” are defined with respectto the conventional plane or surface being on the top or exposed surfaceof the substrate, regardless of the orientation of the substrate; andwhile “on” is intended to suggest a direct contact of one structurerelative to another structure which it lies “on”(in the absence of anexpress indication to the contrary); the terms “over” and “under” areexpressly intended to identify a relative placement of structures (orlayers, features, etc.), which expressly includes—but is not limitedto—direct contact between the identified structures unless specificallyidentified as such. Similarly, the terms “over” and “under” are notlimited to horizontal orientations, as a structure can be “over” areferenced structure if it is, at some point in time, an outermostportion of the construction under discussion, even if such structureextends vertically relative to the referenced structure, rather than ina horizontal orientation.

The terms “wafer” and “substrate” are used herein to refer generally toany structure on which integrated circuits are formed, and also to suchstructures during various stages of integrated circuit fabrication. Thefollowing detailed description is, therefore, not to be taken in alimiting sense, and the scope of the various embodiments is defined onlyby the appended claims, along with the full scope of equivalents towhich such claims are entitled.

Various embodiments according to the present disclosure and describedherein include memory utilizing a vertical structure of memory cells(e.g., NAND strings of memory cells). As used herein, directionaladjectives will be taken relative a surface of a substrate upon whichthe memory cells are formed (i.e., a vertical structure will be taken asextending away from the substrate surface, a bottom end of the verticalstructure will be taken as the end nearest the substrate surface and atop end of the vertical structure will be taken as the end farthest fromthe substrate surface).

As used herein, directional adjectives, such as horizontal, vertical,normal, parallel, perpendicular, etc., can refer to relativeorientations, and are not intended to require strict adherence tospecific geometric properties, unless otherwise noted. For example, asused herein, a vertical structure need not be strictly perpendicular toa surface of a substrate, but can instead be generally perpendicular tothe surface of the substrate, and can form an acute angle with thesurface of the substrate (e.g., between 60 and 120 degrees, etc.).

As used herein, the term actuate and operate can be usedinterchangeably, such as to indicate operations, or activity that causesa physical or logical change in the state of a signal, a circuit, ordata object.

According to one or more embodiments of the present disclosure, a memorycontroller (e.g., a processor, controller, firmware, etc.) locatedinternal or external to a memory device, is capable of determining(e.g., selecting, setting, adjusting, computing, changing, clearing,communicating, adapting, deriving, defining, utilizing, modifying,applying, etc.) a quantity of wear cycles, or a wear state (e.g.,recording wear cycles, counting operations of the memory device as theyoccur, tracking the operations of the memory device it initiates,evaluating the memory device characteristics corresponding to a wearstate, etc.)

According to one or more embodiments of the present disclosure, a memoryaccess device can be configured to provide wear cycle information to thememory device with each memory operation. The memory device controlcircuitry (e.g., control logic) can be programmed to compensate formemory device performance changes corresponding to the wear cycleinformation. The memory device can receive the wear cycle informationand determine one or more operating parameters (e.g., a value,characteristic) in response to the wear cycle information.

It will be understood that when an element is referred to as being “on,”“connected to” or “coupled with” another element, it can be directly on,connected, or coupled with the other element or intervening elements canbe present. In contrast, when an element is referred to as being“directly on,” “directly connected to” or “directly coupled with”another element, there are no intervening elements or layers present. Iftwo elements are shown in the drawings with a line connecting them, thetwo elements can be either be coupled, or directly coupled, unlessotherwise indicated.

Method examples described herein can be machine or computer-implementedat least in part. Some examples can include a computer-readable mediumor machine-readable medium encoded with instructions operable toconfigure an electronic device to perform methods as described in theabove examples. An implementation of such methods can include code, suchas microcode, assembly language code, a higher-level language code, orthe like. Such code can include computer readable instructions forperforming various methods. The code can form portions of computerprogram products. Further, the code can be tangibly stored on one ormore volatile or non-volatile tangible computer-readable media, such asduring execution or at other times. Examples of these tangiblecomputer-readable media can include, but are not limited to, hard disks,removable magnetic disks, removable optical disks (e.g., compact disksand digital video disks), magnetic cassettes, memory cards or sticks,random access memories (RAMs), read only memories (ROMs), and the like.

Example 1 is a storage system comprising: a controller circuitcomprising a volatile memory; a non-volatile memory; and a resetcircuit, the reset circuit configured to: receive a reset signal from ahost device; actuate a timer circuit, the timer circuit configured tocause the storage device to reset after a threshold time period; andactuate the controller circuit to write data stored in the volatilememory to the non-volatile memory during the threshold time period.

In Example 2, the subject matter of Example 1 is optionally configuredsuch that to actuate the controller circuit, the reset circuit isconfigured to generate an interrupt signal to interrupt a processexecuted by the controller circuit; and in response to receiving theinterrupt signal, the controller circuit is configured to write the datastored in the volatile memory to the non-volatile memory.

In Example 3, the subject matter of any of Examples 1-2 is optionallyconfigured such that in response to receiving the signal, the controllercircuit is configured to disable the timer circuit to prevent anautomatic reset of the storage device in response to expiration of thethreshold time period.

In Example 4, the subject matter of any of Examples 1-3 is optionallyconfigured such that in response to receiving the interrupt signal, thecontroller circuit is configured to reset the storage device afterwriting the data stored in the volatile memory to the non-volatilememory.

In Example 5, the subject matter of any of Examples 1-4 is optionallyconfigured such that the data stored in the volatile memory compriseshost data received from the host device, the controller circuitconfigured to temporarily store the host data in the volatile memorybefore writing the host data to the non-volatile memory.

In Example 6, the subject matter of any of Examples 1-5 is optionallyconfigured such that the controller circuit comprises the reset circuit.

In Example 7, the subject matter of any of Examples 1-6 is optionallyconfigured such that the reset circuit comprises the timer circuit.

In Example 8 is a method comprising: receiving a reset signal at astorage device; after receiving the reset signal, the storage devicecounting for a threshold time period before resetting the storagedevice; and after receiving the reset signal and during the thresholdtime period, writing data stored in a volatile memory of the storagedevice to a non-volatile memory of the storage device before the storagedevice is reset.

In Example 9, the subject matter of Example 8 is optionally configuredsuch that the storage device comprises a controller which includes thevolatile memory; and comprising: suspending execution of one or moreprocesses of the controller; and causing the controller to write thedata stored in the volatile memory to the non-volatile memory.

In Example 10, the subject matter of any of Examples 8-9 is optionallyconfigured such that suspending execution of one or more processescomprises causing a processor interrupt in the controller.

In Example 11, the subject matter of any of Examples 8-10 is optionallyconfigured to cause the controller to reset the storage device afterwriting the data stored in the volatile memory to the non-volatilememory.

In Example 12, the subject matter of any of Examples 8-11 is optionallyconfigured to cause the controller to prevent an automatic reset of thestorage device in response to expiration of the threshold time period.

In Example 13, the subject matter of any of Examples 8-12 is optionallyconfigured to cause the controller to extend the threshold time period.

In Example 14, the subject matter of any of Examples 8-13 is optionallyconfigured to resetting the storage device in response to expiration ofthe threshold time period.

In Example 15 is a machine-readable storage medium that providesinstructions that, when executed by a controller of a storage devicecause the storage device to perform operations comprising: receiving areset signal; after receiving the reset signal, counting for a thresholdtime period before resetting the storage device; and after receiving thereset signal and during the threshold time period, writing data storedin a volatile memory of the storage device to a non-volatile memory ofthe storage device before the storage device is reset.

In Example 16, the subject matter of Example 15 is optionally configuredsuch that the operations comprise suspending execution of one or moreprocesses of a controller in the storage device and causing thecontroller to write the data stored in the volatile memory to thenon-volatile memory.

In Example 17, the subject matter of any of Examples 15-16 is optionallyconfigured such that suspending execution of one or more processescomprises causing a processor interrupt in the controller.

In Example 18, the subject matter of any of Examples 15-17 is optionallyconfigured such that the operations comprise causing the controller toreset the storage device after writing the data stored in the volatilememory to the non-volatile memory.

In Example 19, the subject matter of any of Examples 15-18 is optionallyconfigured such that the operations comprise causing the controller toprevent an automatic reset of the storage device at the expiration ofthe threshold time period.

In Example 20, the subject matter of any of Examples 15-19 is optionallyconfigured such that the operations comprising resetting the storagedevice in response to expiration of the threshold time period.

Example 21 is at least one machine-readable medium includinginstructions that, when executed by processing circuitry, cause theprocessing circuitry to perform operations to implement of any ofExamples 1-20.

Example 22 is an apparatus comprising means to implement of any ofExamples 1-20.

Example 23 is a system to implement of any of Examples 1-20.

Example 24 is a method to implement of any of Examples 1-20.

The above description is intended to be illustrative, and notrestrictive. For example, the above-described examples (or one or moreaspects thereof) can be used in combination with each other. Otherembodiments can be used, such as by one of ordinary skill in the artupon reviewing the above description. The Abstract is provided to complywith 37 C.F.R. § 1.72(b), to allow the reader to quickly ascertain thenature of the technical disclosure. It is submitted with theunderstanding that it will not be used to interpret or limit the scopeor meaning of the claims. Also, in the above Detailed Description,various features can be grouped together to streamline the disclosure.This should not be interpreted as intending that an unclaimed disclosedfeature is essential to any claim. Rather, inventive subject matter canlie in less than all features of a particular disclosed embodiment.Thus, the following claims are hereby incorporated into the DetailedDescription, with each claim standing on its own as a separateembodiment, and it is contemplated that such embodiments can be combinedwith each other in various combinations or permutations. The scope ofthe invention should be determined with reference to the appendedclaims, along with the full scope of equivalents to which such claimsare entitled.

What is claimed is:
 1. A memory device, comprising: a non-volatilememory array; a volatile memory array; a communication interfacecomprising a first reset input configured to receive a first resetsignal from an external device; a storage controller comprising a secondreset input and a processor operable to execute instructions to performoperations of the memory device; and reset logic interposed between thefirst and second reset inputs, the reset logic configured to: receivethe first reset signal from the external device; actuate a timercircuit, the timer circuit configured to cause the memory device toreset after a specified threshold time duration; initiate transfer ofdata from the volatile memory array to the non-volatile memory array;and responsive to expiration of the timer circuit, provide a secondreset signal to the second reset input to trigger reset of the memorydevice.
 2. The memory device of claim 1, wherein the storage controllercomprises the reset logic.
 3. The memory device of claim 1, wherein thememory device is a Universal Flash Storage (UFS) device, and wherein thenon-volatile memory array comprises one or more NAND memory devices. 4.The memory device of claim 1, wherein the reset logic is configured toprovide an interrupt signal to the storage controller in response toreceiving the first reset signal at the first reset input; andresponsive to the interrupt signal, the storage controller is configuredto interrupt a current routine of the memory device and initiate a resetroutine of the memory device.
 5. The memory device of claim 4, whereinthe reset routine includes a data flush routine to transfer data fromthe volatile memory array to the non-volatile memory array.
 6. Thememory device of claim 4, wherein responsive to the interrupt signal,the storage controller is configured to deactivate the timer circuit. 7.The memory device of claim 4, wherein responsive to the interruptsignal, the storage controller is configured to reset the memory deviceafter transfer of the data from the volatile memory array to thenon-volatile memory array.
 8. The memory device of claim 1, wherein thereset logic is configured to initiate the transfer of data from thevolatile memory array to the non-volatile memory array during or withinthe specified threshold time duration.
 9. The memory device of claim 1,wherein the volatile memory array comprises a static random accessmemory (SRAM) write cache.
 10. The memory device of claim 1, wherein thestorage controller comprises a timer disable output configured toprovide a disable signal to the reset logic to disable the timercircuit.
 11. The memory device of claim 1, wherein the storagecontroller is configured to change the specified threshold timeduration.
 12. A system comprising: a host device comprising a firstreset output and a data interface; a non-volatile memory circuit; acache memory circuit; a storage controller comprising a second resetinput and a processor configured to execute instructions to performoperations using the non-volatile memory circuit and the cache memorycircuit; and reset logic including a first reset input and a secondreset output, the first reset input of the reset logic coupled to thefirst reset output of the host device, and the second reset output ofthe reset logic coupled to the second reset input of the storagecontroller, the reset logic configured to: receive a first reset signalfrom the host device; actuate a timer, the timer configured to cause thestorage controller to execute a reset routine after a specifiedthreshold time duration; initiate transfer of data from the cache memorycircuit to the non-volatile memory circuit; and responsive to expirationof the timer, provide a second reset signal to the second reset input toinitiate the reset routine.
 13. The system of claim 12, comprising amemory device that includes the non-volatile memory circuit, the cachememory circuit, the storage controller, and the reset logic.
 14. Thesystem of claim 13, wherein the cache memory circuit comprises a portionof the storage controller and is configured to temporarily storeinformation received from the host device via the data interface beforethe information is transferred to the non-volatile memory circuit. 15.The system of claim 12, wherein the reset logic is configured to providean interrupt signal to the storage controller in response to receivingthe first reset signal; and responsive to the interrupt signal, thestorage controller is configured to interrupt a current routine of theprocessor and initiate the reset routine.
 16. The system of claim 15,wherein the reset routine includes a data flush routine to transfer datafrom the cache memory circuit to the non-volatile memory circuit. 17.The system of claim 15, wherein responsive to the interrupt signal, thestorage controller is configured to deactivate the timer.
 18. The systemof claim 12, wherein the reset logic comprises a timer disable input,wherein the storage controller comprises a timer disable output coupledto the timer disable input, and wherein the storage controller isconfigured to provide a timer disable signal to the timer disable inputof the reset logic to disable the timer.
 19. A circuit comprising: resetlogic for a memory device, the reset logic including a first resetinput, a timer disable input, an interrupt signal output, and a resetoutput, wherein the reset logic is configured to: receive a first resetsignal from a memory host device; actuate a timer, the timer configuredto cause the memory device to reset after a specified threshold timeduration; initiate transfer of data from a volatile memory to anon-volatile memory; and responsive to expiration of the timer, providea second reset signal using the reset output to trigger reset of thememory device.
 20. The circuit of claim 19, further comprising acontroller for the memory device, wherein the reset logic is configuredto provide an interrupt signal to the controller in response toreceiving the first reset signal; and responsive to the interruptsignal, the controller is configured to interrupt a current routine ofthe memory device and initiate a reset routine of the memory device, ordeactivate the timer, or reset the memory device after transferring datafrom the volatile memory to the non-volatile memory.